U.S. patent application number 11/298159 was filed with the patent office on 2006-06-15 for water feed controller for a boiler.
Invention is credited to Jeffrey C. Merwin.
Application Number | 20060124078 11/298159 |
Document ID | / |
Family ID | 36585901 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060124078 |
Kind Code |
A1 |
Merwin; Jeffrey C. |
June 15, 2006 |
Water feed controller for a boiler
Abstract
A water feed controller which can provide for the addition of a
preset fixed amount of water to be added after a low water
condition is removed. This system provides for a preset fixed
amount of water to be added to a boiler above the amount which
triggers the low water condition. This generally inhibits excess
cycling from the boiler operating at its minimum safe water level
as well as inhibiting overfilling of the boiler. Further, there is
discussed a water feed controller which can measure the amount of
water added over a prior predetermined period (such as 30 days)
which serves as a floating window of time so that a leak or other
condition resulting in overly frequent filling can be detected
quickly.
Inventors: |
Merwin; Jeffrey C.; (St.
Charles, MO) |
Correspondence
Address: |
LEWIS, RICE & FINGERSH, LC;ATTN: BOX IP DEPT.
500 NORTH BROADWAY
SUITE 2000
ST LOUIS
MO
63102
US
|
Family ID: |
36585901 |
Appl. No.: |
11/298159 |
Filed: |
December 9, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60634696 |
Dec 9, 2004 |
|
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|
Current U.S.
Class: |
122/451R |
Current CPC
Class: |
F22D 5/26 20130101; F22D
11/003 20130101; Y10T 137/86413 20150401; F22B 37/46 20130101; Y10T
137/7306 20150401 |
Class at
Publication: |
122/451.00R |
International
Class: |
F22D 5/26 20060101
F22D005/26 |
Claims
1. A water feed controller for a boiler, the controller comprising:
electronics for monitoring the signal from a low water cut-off
(LWCO); electronics for opening and closing a water path; and a
processor; wherein when said electronics for monitoring detect a
low water signal from said LWCO, said processor initiates opening
of said water path to allow water to flow into said boiler; wherein
said water path remains open until said LWCO ceases signaling a low
water condition; and wherein said processor allows said water path
to remain open after said LWCO ceases signaling said low water
condition, so a preset fixed amount of water is added into said
boiler after said LWCO ceases signaling said low water
condition.
2. The water feed controller of claim 1 wherein said preset fixed
amount is set when said water feed controller is installed.
3. The water feed controller of claim 1 further comprising: a flood
lockout system, said flood lockout system closing said water path
and not allowing said water path to reopen if the combined amount
of water added to said boiler both prior to said LWCO ceasing
signaling a low water condition and added after the LWCO ceased
signaling a low water condition, is over a predetermined maximum
amount of water.
4. The water feed controller of claim 3 wherein said flood lockout
system also indicates to a human user that said combined amount of
water is over said predetermined maximum amount of water.
5. The water feed controller of claim 4 wherein said indication is
sent to a remote location.
6. The water feed controller of claim 1 wherein said preset fixed
amount of water is determined by the setting of a Hold After Water
ok (HAW) switch.
7. A water feed controller for a boiler, the controller comprising:
means for detecting a low water condition in said boiler; and means
for opening and closing a water path into said boiler; wherein when
said means for detecting detects a low water condition, said means
for opening and closing opens said water path to allow water to
flow into said boiler; wherein said means for opening and closing
maintains said open water path until said means for detecting no
longer detects said low water condition; and wherein said means for
opening and closing does not close said open water path, until a
preset fixed amount of water is added into said boiler after said
means for detecting no longer detects said low water condition.
8. The water feed controller of claim 7 further comprising: flood
lockout means for closing said water path and not allowing said
water path to reopen if the total amount of water added while said
water path was open is over a predetermined maximum amount of
water.
9. The water feed controller of claim 8 further comprising alarm
means for notifying a human user that said total amount of water
added is over said predetermined maximum amount of water.
10. The water feed controller of claim 9 wherein said alarm means
notifies a human user located remotely of said water feed
controller.
11. A method for feeding water to a boiler, the method comprising
the steps of: detecting a low water condition in said boiler;
opening a water path to allow water to flow into said boiler;
waiting for said low water condition to cease; allowing said water
path to remain open until a preset fixed additional amount of water
has been added to said boiler after said low water condition
ceased; and closing said water path.
12. The method of claim 11 further comprising the step of:
repeating the steps of the method every time a low water condition
is detected.
13. The method of claim 12 further comprising the steps of:
determining if the total amount of water added during the last
instance of said method is over a predetermined maximum amount of
water; and if said total amount of water added during said last
instance is above said predetermined maximum amount of water,
inhibiting said step of repeating.
14. The method of claim 13 wherein if said total amount of water is
above a predetermined maximum amount, the step of closing is
immediately performed.
15. The method of claim 14 further comprising: triggering an alarm
condition if said amount of water added during said last instance
is above said predetermined maximum amount of water.
16. The method of claim 12 further comprising the steps of:
determining if the total amount of water added during all instances
of said method occurring within a predetermined period of time is
over a predetermined maximum amount of water; and if said total
amount of water added during all instances of said method occurring
within said predetermined period of time is above a predetermined
maximum amount of water, not performing said step of repeating.
17. The method of claim 16 further comprising: triggering an alarm
condition is said total amount of water added during all instances
of said method occurring within said predetermined period of time
is above said predetermined maximum amount.
18. A system for controlling water feed to a boiler, the system
comprising: electronics for monitoring the signal from a low water
cut-off (LWCO); electronics for opening and closing a water path
into said boiler; and a processor having a clock source; wherein
when said electronics for monitoring detect a low water signal from
said LWCO, said processor initiates opening of said water path to
allow water to flow into said boiler; wherein which said processor
determines when said boiler has sufficient water to close said
water path to said boiler, said electronics close said water path;
wherein said processor adds the amount of water added between the
instance of opening and closing the water path to a value
representative of the water added for a sub-period of time
determined by said clock source; wherein at the end of said
sub-period of time, said processor writes said value for said
sub-period to a memory; and wherein said processor computes the
total amount of water added in a period by adding the values for
the immediately prior sub-periods forming that period; and wherein
if said amount is over a preset limit, triggers an alarm
condition.
19. The system of claim 18 wherein said period comprises 30
days.
20. The system of claim 18 wherein said sub-period comprises one
day.
21. The system of claim 18 wherein when said alarm condition is
triggered, said system will not allow additional water to be added
to said boiler during the current sub-period.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 60/634,696 filed Dec. 9, 2004, the
entire disclosure of which is herein incorporated by reference.
(1) FIELD OF THE INVENTION
[0002] The present invention relates to a water feed controller or
control system for use with a boiler. Particularly to water feed
controllers which can provide for a preset fixed amount of water to
a boiler after a low water condition is eliminated and which can
provide for a floating window indicating when total water additions
during a prior time period have exceeded specified thresholds.
(2) BACKGROUND OF THE INVENTION
[0003] Boilers have been used for generating steam in radiant
heating systems in both residential and commercial applications for
a number of years. The systems generally operate by heating boiler
water to produce steam. The steam is then distributed through a
piping system to distribute heat to the facility by having the
distributed steam transfer heat to surrounding air. Once
distributed, the resultant steam condenses and returns to the
boiler to be heated again and redistributed.
[0004] Because of the way these boiler systems operate, it is
necessary that there be sufficient water in the boiler system at
all times. If the water level drops too low, the water in the
boiler can flash to steam explosively, seriously injuring or
killing people or damaging the boiler, facility or both. Steam
boiler systems can also be damaged if they have too much water. In
this case, liquid water can be forced from the boiler into the
pipes along with the high-velocity steam which can lead to damage
of piping, valves, or heating system components such as radiators.
For these reasons, boiler systems are filled to their desired level
during installation. They then include a Low Water Cutoff (LWCO)
which will serve to turn off the heat source in the boiler if the
water level drops below a safe level. The LWCO therefore serves as
a protector against the system being operated with insufficient
water and indicates that additional water needs to be added.
[0005] Historically, additional water was added manually to the
boiler when the LWCO indicated a low water condition or boiler
water levels were observed to be below normal operating levels.
This was effective with sufficiently educated maintenance personnel
in preventing overfilling. However, it was highly inconvenient and,
if no one was around, could result in the boiler not providing heat
until it was attended to. Therefore, recently, the water has been
preferably added by mechanical or electronic water feed
controllers.
[0006] Automatic water addition systems traditionally operated by
adding water to the boiler until the LWCO no longer indicated a low
water condition. At that time, the water level was presumed in a
safe range and the heating source of the boiler could be enabled
without risk of damage to the boiler. These systems, however,
suffered from a series of problems.
[0007] The traditional role of the LWCO is to shut down boiler heat
sources in the event that the water level is below a safe level,
which is typically well below an optimum operating level. In
addition to this function, the LWCO was configured to operate water
feeding devices to replenish low water levels. The LWCO also serves
to shut off the water feeding devices once the LWCO is satisfied by
the water level. In particular, the LWCO was basically a switch
that transferred power from the boiler's heating source to the
automatic water feeder when a low water condition was detected and
reversed the transfer once the low water condition was no longer
detected. The system, therefore, automatically fed an amount of
water into the boiler until the water level satisfied the LWCO. As
it is a common practice for LWCO devices to be installed in such a
manner that they operate slightly above the boiler's minimum safe
water level, boiler systems that are automatically fed as noted
above will be operating near at the boiler's minimum safe water
level and generally no higher.
[0008] It is desirable in a boiler system to operate at a water
level above the minimum safe water level for numerous reasons.
First, operation above the minimum safe level provides an
additional safety margin by adding hysteresis to the water level.
Further, operating above the minimum safe level compensates for
dynamic water levels due to boiling and surging of the boiler
water. This prevents short-cycling of the boiler's burner due to
the LWCO detecting these dynamic water levels caused by
insufficient hysteresis in the water level. If the boiler is firing
and it short-cycles due to these dynamic water levels, the burner
controls are turned off in favor of the water feed. This cuts the
heating cycle short and can cause flue gases to condense on
internal boiler components. Over time, this reduces the life of
heat exchangers and other critical components in the boiler and can
lead to premature failures and costly repairs. When operating near
the probe level of the LWCO, a slight leak, or even a fluctuation
of the LWCO switch mechanism, can result in the burner being
short-cycled unnecessarily.
[0009] Further, as a boiler system steams, water is converted to
steam thereby lowering the water level of the boiler. This steam
has a transit time as it passes through the heating system,
condenses, and returns to the boiler as water. If the water level
falls below the LWCO before the condensate returns to the boiler,
the LWCO can detect a low water condition and initiate a water feed
cycle. Depending on the delay in the condensate returning to the
boiler, enough water may feed into the boiler that, when combined
with the returned condensate, the boiler will be overfilled and
flooded.
[0010] To deal with the problem of the water being prematurely fed
due to the delay of returning condensate, delays have been added to
some automatic water feeds so that the system's water level has a
chance to stabilize before additional water is added. In
particular, water is not added until a period of delay occurs after
the LWCO was triggered. Therefore, the water was allowed to
condense and return to the boiler so that the actual water level
could be determined before water was added. This helped eliminate
potential overfilling but can also result in increased
short-cycling of the burner, when operating at the minimum water
level.
[0011] To try and provide waterabove the minimum level in an
automatic system, there are generally two possible methodologies
for putting additional water into the boiler regardless of whether
a delay after LWCO low water condition is used or not. In a
simplistic case, water can be manually fed into the boiler system
by a user pressing a manual feed button on the water feed
controller essentially overriding the LWCO automatic feed to add
more water. While this is effective, it requires a human user to
operate the manual feed and to guess at how much water has been
supplied (and needs to be supplied) to the boiler and provides
little improvement over the original manual system.
[0012] In the alternative, the water feeder can be set to feed a
fixed number of gallons into the boiler system each time the LWCO
indicates a low water condition instead of simply filling until the
LWCO no longer indicates a low water condition. When feeding a
fixed number of gallons, it is required that the installer test the
boiler system to identify precisely how much water a feed cycle
must provide to prevent the feed cycle from accidentally
overfilling the boiler. The water feeder must then be programmed to
dispense that amount of water when the LWCO condition exists. The
amount of water will be variable due to the water capacities of
different models of boilers. An error in identifying the amount of
water to be fed can lead to an insufficient amount of water, or too
much water, being fed into the boiler. Insufficient water can lead
to additional feed cycles being initiated by the water feeder,
potentially overfilling and flooding the boiler. Similarly, if the
amount of water that is programmed to be fed into the boiler is too
large it is possible to overfill the boiler system. This flooding
or overfilling of the boiler can prevent proper steam generation or
result in water being propelled into the steam piping, damaging the
piping systems.
[0013] In addition to the issues noted above, these systems still
have further problems. If the boiler (or related components) was
leaking, the continual water feeds would keep the water at a safe
operating level, but would introduce a continual supply of fresh
(oxygenated) water. This oxygenated water leads to increased
corrosion in the boiler system and results in premature failure of
the heating system.
[0014] All boilers will lose some water over time. The issue in
determining whether water loss is significant enough to warrant
replacement or repair requires examining how much additional water
the system is requiring over a period of time (generally 30 days).
As a leak will generally result in a steady loss, the only way to
determine if a leak or other problem is sufficient to require
action is to measure the amount of water added in a recent time
period or to normalize loss to the calibration time period.
[0015] U.S. Pat. No. 6,688,329, the entire disclosure of which is
herein incorporated by reference, is directed to one methodology
for determining if excessive feed has been provided which could
indicate that the boiler has a leak. The system described therein
uses a display counter that indicates the number of gallons that
the water feeder has dispensed since its totals were last reset.
This display, therefore, provides water consumption information
from which consumption over time can be computed.
[0016] This determination, however, requires extensive record
keeping and manual computation. In particular, users must manually
log the number of gallons shown on the display every 30 days so as
to determine the 30 day usage rate. This is a complicated schedule
to follow as it does not align with any calendar calculations and
in most applications is impractical. In practice, users get the
amount after some period, determine the length of the period, and
normalize the amount of water used to a 30 day period. This number
must then be manually compared against the manufacturer's expected
water usage that must be found in water feeder or boiler
documentation and can differ among boilers. This process is both
manually cumbersome and fraught with the possibility of human
error. Further, the process of normalization also introduces
inaccuracies. In particular, as the period is not necessarily the
same and water will be added as a batch when added, the
normalization can serve to skew calculations such that the 30 day
usage is too low or too high depending on whether fill actions
occurred just outside, or just inside the measurement period.
[0017] Therefore, if the user does not record the water amounts
from the display at reasonably consistent time intervals, the
manual computation becomes more complicated and can become less
accurate (as trends may not be as apparent or may end up averaged
out over time). Further, the system relies on a person to correctly
log usage data and to determine that excess usage is taking place.
Therefore, the possibility of the introduction of human error is
high and the indicators may not be reset or numbers may be recorded
incorrectly. Further, if service personnel change, the new
personnel may not know how or where the old data was recorded and
may need to start essentially from zero.
[0018] There is still one additional problem with this methodology.
Because the counter can be reset when the measurement is made, the
measurements only occur at particular instances which are cyclical
(generally with a minimum 30 days) and occur generally only once
every time period. If the boiler developed a major leak soon after
the water use for the prior 30-day period was recorded, the leak
may cause significant damage before the next check (around 30 days
later) would determine that a leak had even occurred. Further, with
regards to smaller leaks, it could actually take three or more
different measurement periods before a leak condition would become
apparent to a user. This is because the fill activities generally
will occur sporadically and an increase in the fill in the
normalized period may not be recognized as a leak, but may instead
simply be thought to be due to having an additional and expected
fill event fall in the time between measurements.
[0019] In general, the existing practice of cyclical observation
prohibits relatively real-time notification that excessive water
use is taking place and can allow for error situations to be missed
(or incorrectly detected) due to natural fluctuations within the
periods of measurement.
SUMMARY OF THE INVENTION
[0020] Because of these and other problems in the art, described
herein are systems and methods related to an automatic water feed
controller for a boiler which provides for improved filling of the
boiler to a level in the generally preferred operating range and
above the minimum safe operating level and which also provides for
automatic, near real time, detection of a potential leak
condition.
[0021] Described herein, among other things is a water feed
controller for a boiler, the controller comprising: electronics for
monitoring the signal from a low water cut-off (LWCO); electronics
for opening and closing a water path; and a processor; wherein when
said electronics for monitoring detect a low water signal from said
LWCO, said processor initiates opening of said water path to allow
water to flow into said boiler; wherein said water path remains
open until said LWCO ceases signaling a low water condition; and
wherein said processor allows said water path to remain open after
said LWCO ceases signaling said low water condition, so a preset
fixed amount of water is added into said boiler after said LWCO
ceases signaling said low water condition.
[0022] In an embodiment of the controller, the preset fixed amount
is set when said water feed controller is installed or the preset
fixed amount of water is determined by the setting of a Hold After
Water ok (HAW) switch.
[0023] In an embodiment of the controller, the controller also
includes: a flood lockout system, said flood lockout system closing
said water path and not allowing said water path to reopen if the
combined amount of water added to said boiler both prior to said
LWCO ceasing signaling a low water condition and added after the
LWCO ceased signaling a low water condition, is over a
predetermined maximum amount of water.
[0024] The flood lockout system may also indicate to a human user
that said combined amount of water is over said predetermined
maximum amount of water and the indication may be sent to a remote
location.
[0025] There is also described herein a water feed controller for a
boiler, the controller comprising: means for detecting a low water
condition in said boiler; and means for opening and closing a water
path into said boiler; wherein when said means for detecting
detects a low water condition, said means for opening and closing
opens said water path to allow water to flow into said boiler;
wherein said means for opening and closing maintains said open
water path until said means for detecting no longer detects said
low water condition; and wherein said means for opening and closing
does not close said open water path, until a preset fixed amount of
water is added into said boiler after said means for detecting no
longer detects said low water condition.
[0026] In an embodiment of the controller there is included a flood
lockout means for closing said water path and not allowing said
water path to reopen if the total amount of water added while said
water path was open is over a predetermined maximum amount of
water.
[0027] In an embodiment, of the controller there is included an
alarm means for notifying a human user that said total amount of
water added is over said predetermined maximum amount of water. The
alarm means may notify a human user located remotely of said water
feed controller.
[0028] There is also described herein, a method for feeding water
to a boiler, the method comprising the steps of: detecting a low
water condition in said boiler; opening a water path to allow water
to flow into said boiler; waiting for said low water condition to
cease; allowing said water path to remain open until a preset fixed
additional amount of water has been added to said boiler after said
low water condition ceased; and closing said water path.
[0029] In an embodiment of the method there may also be included
the steps of: repeating the steps of the method every time a low
water condition is detected; and determining if the total amount of
water added during the last instance of said method is over a
predetermined maximum amount of water, and if said total amount of
water added during said last instance is above said predetermined
maximum amount of water, inhibiting said step of repeating. If said
total amount of water is above a predetermined maximum amount, the
step of closing may be immediately performed and an alarm condition
may be triggered if said amount of water added during said last
instance is above said predetermined maximum amount of water.
[0030] An embodiment of the method may also include the steps of:
determining if the total amount of water added during all instances
of said method occurring within a predetermined period of time is
over a predetermined maximum amount of water; and if said total
amount of water added during all instances of said method occurring
within said predetermined period of time is above a predetermined
maximum amount of water, not performing said step of repeating. An
alarm condition may also be triggered if said total amount of water
added during all instances of said method occurring within said
predetermined period of time is above said predetermined maximum
amount.
[0031] There is also described herein, a system for controlling
water feed to a boiler, the system comprising: electronics for
monitoring the signal from a low water cut-off (LWCO); electronics
for opening and closing a water path into said boiler; and a
processor having a clock source; wherein when said electronics for
monitoring detect a low water signal from said LWCO, said processor
initiates opening of said water path to allow water to flow into
said boiler; wherein which said processor determines when said
boiler has sufficient water to close said water path to said
boiler, said electronics close said water path; wherein said
processor adds the amount of water added between the instance of
opening and closing the water path to a value representative of the
water added for a sub-period of time determined by said clock
source; wherein at the end of said sub-period of time, said
processor writes said value for said sub-period to a memory; and
wherein said processor computes the total amount of water added in
a period by adding the values for the immediately prior sub-periods
forming that period; and wherein if said amount is over a preset
limit, triggers an alarm condition.
[0032] In an embodiment the period may comprise 30 days and said
sub-period comprise one day. Further, when said alarm condition is
triggered, said system may not allow additional water to be added
to said boiler during the current sub-period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 shows an overview of an embodiment of a water feed
controller installed in a boiler water supply.
[0034] FIG. 2 shows a general internal view of the components of an
embodiment of a water feed controller.
[0035] FIG. 3 provides a block diagram of elements of an embodiment
of a water feed controller.
[0036] FIG. 4 provides a flowchart of the steps for performing a
fill operation.
[0037] FIG. 5 provides a flowchart for the steps of determining an
excess feed indication.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] FIG. 1 provides for an embodiment of a water feed controller
(101) in a piping setup to feed a boiler. The water feed controller
(101) will generally be installed on a pipe bypass including valves
(103) to allow for the water feed controller (101) to be isolated
from the main water line (107), if necessary. This isolation
provides for the ability to perform maintenance on the water feed
controller (101) or to take the water feed controller (101) out of
the water path in the event of malfunction. There will generally be
a manual by-pass valve (105) in the main water line (107) to allow
for filling the boiler upon initial installation or refilling when
the water feed controller (101) has been isolated or is not in
service.
[0039] FIG. 2 provides for an overview of the internal components
of an embodiment of a water feed controller (101). Another
embodiment is shown in the block diagram of FIG. 3. In particular,
FIGS. 2 and 3 show a water feed controller (101) including a feed
status indicator (201), an excess feed reset (203), a switch for
setting the low water cut-off (LWCO) delay timer cycle (205), a
switch for setting excess feed triggers (207) and a switch for
setting feed (209) and Hold After Water ok (HAW) (211) amounts. The
depicted embodiment also includes a manual fill button (213) which
allows the user to add water to the boiler regardless of any
determination by the LWCO that additional water is necessary or to
reset a flood lockout condition. The embodiment will generally also
comprise a power supply (221), electronics for monitoring the
signal from an LWCO (223), electronics for controlling a solenoid
valve (225), and a solenoid valve (227) for opening and closing the
water path for the feeding of additional water as shown in FIG.
3.
[0040] An embodiment of the operation of the water feed controller
(101) as shown in FIGS. 2 and 3 is shown in FIG. 4. The water feed
controller shown in FIGS. 2 and 3 provides for two different feed
modes depending on the manner which the user would like to add
water and have the system operate as shown by the parallel arms on
the flowchart of FIG. 4. The different feed levels are selected by
the user during installation and may later be changed. In FIG. 4
the first step is the indication that the LWCO is at a low water
condition (301) indicating that additional water needs to be added
to the boiler. The system will validate the low water signal as an
accurate indicator of low water in step (303). If the low water
signal is valid (305), the system then proceeds with any programmed
delay (307). Otherwise, sufficient water is still present and a
feed is not necessary. When a period of delay is used, this period
will generally be set by the water feeder's delay timer (205) prior
to the low-water condition occurring. Once any delay (307) expires,
the system must determine which mode it is in, LWCO mode or fixed
fill mode, in step (309) if the LWCO is still indicating a low
water condition.
[0041] In the fixed fill mode, water is added in step (329). As
water is added, the system determines if a flood condition criteria
has been met in step (331). In this determination, the system will
determine if too much water has been added and there are concerns
about flooding. If a flood condition may exist in step (331) a
flood lockout is initiated at step (325), the water feed stops in
step (327) and the process ends. If there is no flood condition,
the system determines in step (333) if the fixed feed amount has
been added yet. If not, the system continues to feed water in step
(329). Once the fixed amount of water has been added, it is
determined if the LWCO is still reading a low water condition in
step (335). Once the LWCO is no longer reading a low water
condition, the system is deemed filled and the water feed is
stopped in step (327). If, however, the LWCO still reads that there
is a low water condition in step (335), another fixed feed cycle is
initiated. The flood lockout condition of step (325) is principally
designed so that if the system believes too much water has been
added, there may be an error which is either a major leak or the
LWCO has malfunctioned and is no longer correctly reading the water
level. As the malfunction may have led to unnecessary water being
added to the boiler, the system will generally indicate a flood
lockout on feed status indicator (201) in step (325) and may
prohibit the boiler from reactivating or from receiving more water
until it has been checked by maintenance personnel. In this way,
the system can handle a malfunction or a major leak and notify
personnel of the problem very quickly instead of running the system
in what is a potentially damaging configuration. The amount of the
fixed feed may be set by the user using feed switch (209).
[0042] In the LWCO mode, water is fed in step (311) again checking
for a flood condition in step (313) until the LWCO no longer
indicates a low water condition in step (315). At this time, the
water level is above the minimum operating level and the LWCO
switches off. The system next determines if a HAW setting has been
enabled. If not, the cycle is complete and the water feed is
stopped in step (327). This mode therefore generally provides for
automatic fill in the manner of a standard LWCO automatic fill
switch and may be preferable in some situations although it
generally does not allow for filing of water to an optimum
level.
[0043] If a HAW setting has been enabled in step (317), the system
will feed water in step (319) until the HAW amount of water has
been added in step (321). The system will also check to see if a
predetermined "flood level" of water has been fed yet in step
(323). If the flood level has not been met, the water feed
continues. If the level has been met, the system will generally
determine that either the LWCO is malfunctioning, or the system has
developed a major leak and will shut off the water supply and enter
a flood lockout mode in step (325) indicating the lockout on feed
status indicator (201). Once the system has added the predetermined
amount of water in step (321) to meet the HAW setting, which is
generally predetermined by the selected position of HAW switch
(211), the system will automatically stop feeding water in step
(327) as the feed is complete.
[0044] The additional feed time after the LWCO ceases indicating
that there is a low water condition using the HAW setting allows
the boiler system to fill higher than the boiler's minimum safe
water level as defined by the LWCO turning off. This permits the
water level to rise above the level of the LWCO probe or float
mechanism and provide additional water into the system, thus
providing hysteresis for the water level and to reach the boiler
manufacturer's recommended water level. This prevents intermittent
low water conditions and resultant short cycling of the boiler
during calls for heat. One advantage of the HAW mode over other
modes is that in the HAW mode, the water level at boiler
reactivation is generally fairly well known and a relatively known
amount above the minimum level, in the other modes, the level is
usually more variable and/or closer to the minimum. Specifically,
the HAW setting represents a preset fixed amount of water,
preferably defined by a time setting, which is added after the low
water condition is no longer detected. In effect, it's a fixed
amount above the minimum operational level.
[0045] As discussed above in conjunction with FIGS. 2 and 3, one
device which is included in an embodiment is the feed status
indicator (201). In the depicted embodiment, the feed status
indicator (201) is an LED capable of different modes of operation
(such as emitting different colors, blinking or lighting steadily).
In alternative embodiments other indicators may be used including,
but not limited to, visual displays, audio communications,
communications to other equipment, or a combination of the above.
The feed status indicator (201) will generally indicate that the
flood lockout condition has occurred and may also indicate other
statuses such that a feed is currently occurring or that the water
feed controller is operating normally. As discussed above, the
flood lockout condition will generally occur when the system
determines that more water than should be necessary to remove a low
water condition has already been added, and yet the low water
condition persists or additional water is being called for. This
situation will generally be indicative of a failure of the LWCO
such that it is no longer indicating the correct level of water,
incorrect water feeding system setup, or a large leak. Any of these
failures require quick correction and notification to prevent
damage to both the boiler and surrounding area.
[0046] Even without a large leak or other immediate concern, the
boiler can still have problems from a small leak that is
persistent. When a steam boiler system is regularly leaking steam
or water, an automatic water feeder will fill the boiler water to
compensate for the leaks. While this keeps the boiler system
functioning at a safe water level, the continual addition of fresh
water into the boiler can lead to increased corrosion due to the
fresh supply of oxygen contained in the make-up water. This
corrosion shortens the life of the boiler system and eventually
leads to premature failure and repair or replacement of the boiler
system, typically at great cost to the business or home owner.
[0047] The feed status indicator (201) also provides, in the
depicted embodiment, a visible indication that the boiler system is
consuming excessive amounts of water over a specified time period
in addition to the particular fill related situations discussed
above which are more acute repair issues. That is, the system not
only identifies excessive water feeding during a particular feed
cycle which can cause flooding issues, but also recognizes excess
feed from multiple cycles over time which is a more persistent
problem.
[0048] In the depicted embodiment, the operation of the excess feed
indicator preferably will provide for automatic determination of
when too much water has been fed as shown in the steps of the
flowchart of the embodiment of FIG. 5. Excess feed will generally
be determined to exist when the feed exceeds the typical industry
guidelines for water usage over the most recent time period
corresponding to the industry guideline period. To accomplish this
measurement, the system will generally comprise a microprocessor
(229) or similar device capable of making calculations relative to
a real-time clock source. The user will first indicate to the
processor (229) the period of time over which the measurement is to
occur (for example, 30 days) and the maximum amount of water which
should be fed to the boiler in that period of time in step (401).
In particular, a user may set the excess feed control switches
(207). These values will generally be determined based on industry
guidelines. The processor (229) or other device will then monitor
the amount of water added to the boiler over a time period of the
specified length.
[0049] In particular, the system will generally wait until either a
fill event occurs or a sub-period (for instance, an hour or day) in
the period expires in step (402). The processor (229) will then
determine the amount of water added in the sub-period in step (403)
and record that value as the value for the sub-period in step
(407). Generally, as the update occurs for this sub-period, the
processor (229) will delete or overwrite a prior entry for a
similar sub-period which is now outside the period in step (408).
The processor (229) will next take the value for the new sub-period
and add it to a number of prior recorded values by the processor
(229) in step (405) to make up the predetermined period that was
entered in step (401). For instance, if the sub-period is one day
and the period is 30 days, the processor (229) will take the
current value and add to it the value for the prior 29 days which
have been stored in memory associated with the processor (229).
After the addition in step (405), the processor (229) in step (409)
will compare the total to the value set by the user in step (401)
for the total feed in the period. If the value is greater than the
total in step (413), the processor (229) will trigger an indication
of such status in step (411) indicating the condition with feed
status indicator (201). This indication may also lock out
additional water from being provided. If the value is less, the
system will simply maintain monitoring and advance to the next
sub-period.
[0050] It should be recognized that some sub-periods may have no
fill while others may have a relatively large amount due to the
fixed size of the fill in some operations. As the period is
measured by the total number of sub-periods forming the period of
interest closest to the current time, this rolling window will
flatten out the bumps from these fill events and better show water
use trends over time. Further, because of the use of a rolling
window, the system could, if desired, indicate excess feed for a
short period if an unexpected fill event occurs, but could later
automatically reset (remove the condition) once this period has
passed because the monitoring is continuous. This provides that if
a situation occurs which might be problematic, the system indicates
excess feed, but if it is only a spike in water consumption, (due,
for example, to boiler servicing), it is relatively quickly reset
automatically and the spike in water consumption is averaged out by
regular operation. In this way, the system provides for valuable
monitoring by interrelating multiple, different types of fills. For
instance, if boiler service is performed and a relatively large
fill event occurs, the monitoring system may indicate an overage
for 30 days. This may lockout additional water from being added to
the system during those thirty days. If the LWCO indicates a low
water condition during these thirty days, the dual condition can
trigger a more immediate warning. This can be beneficial because
the boiler, after servicing, should not need additional water this
quickly and a potentially inaccurate repair can be quickly
detected.
[0051] This arrangement provides for much more effective monitoring
of the amount of water being fed into the boiler over the period of
time based upon industry guidelines. The system monitors the total
amount of water added in a particular period of time in essentially
a rolling window of that time length which ends close to the
current time. If the period is 30 days, the processor will look at
the most recent 30 days to determine if the system has exceeded the
predetermined total for the period of time and automatically moves
the window as time progresses. In this way, any period of time can
be easily used as there is no dependency on human measurement and
the value is never normalized, but is based on actual use for the
most recent period (the period ending at any given time). Further,
if it is desired to alter the time period, calculations can be made
relatively automatically and easily adjusted to calculate for
45-day, 60-day, or any other length of windows that may be
desired.
[0052] It should be apparent that there is no need to compute usage
by hand or normalize usage for a particular period. Further, if
excessive water amounts were to be fed, that condition will be
detected as soon as the excessive amount is fed instead of having
to wait for an entire additional period for a user to manually note
water usage as in other systems. Further, the system provides for a
regular computation regardless of the length of days in a month,
without having to abide by a complicated schedule of checking, and
can automatically reset if an excess feed condition possibly
exists, but is then shown to not be the case.
[0053] Alternatively, if a fill event occurs indicating a 30-day
overage of water due to a slightly faster fill schedule, the
monitoring can indicate the problem, but will quickly reset as a
leak concern if not indicated as a major concern yet. In effect, as
a leak grows more persistent, the monitoring will be more and more
likely to be indicating a concern at any given time, making leaks
requiring repair much easier to detect when the output of the
monitor is monitored only at limited intervals. Further, a
persistent leak will actually be more persistently indicated.
[0054] This eliminates many of the issues normally associated with
manually recording water usage and computing water usage. Inclusion
of the flow status indicator (201) also allows the user or service
personnel to set a limit for the number of gallons that the boiler
system should use over a set period of time and be notified when
there is a problem. Once the system is installed and set up, it
automatically signals the user when excessive water use has
occurred. This eliminates manual logging, computing, and comparing
the boiler water usage to documented tables to determine if the
boiler system has a potential problem. Further, because the system
preferably includes a rolling time period, the system is
effectively near real time in its calculation. For instance, if
device were to spring a leak on the 31 st day after the
installation using a 30-day period, this leak would probably be
detected long before the 60th day when it would be detected using
the best manual calculation processes. The shutoff of the system
when there is concern can also prevent excess damage from
overfilling or similar problems in the event of danger, while the
automatic reset can prevent spikes in water consumption from
requiring maintenance if the problem is not persistent.
[0055] The embodiment depicted in FIG. 2 uses a visible indicator
such as an LED or other light to signal excessive water use or need
for system maintenance. This provides for a simple and effective
methodology to indicate a flood lockout situation or excessive
water use situation that requires attention. The water feed
controller (101) may, however, be in a basement and may not be
regularly examined by service personnel. Therefore, in an
alternative embodiment, signaling of a flood lockout condition
occurs via a relay or other methodology which allows for the
condition to automatically engage other equipment or to provide for
an alarm or indicator to a remote location. This transmission may
occur in any medium and may send any information including, but not
limited to, using protocols such as RS-485, Firewire (IEEE standard
1394), X10, Ethernet, Arcnet, Bacnet, or Hypertext Transfer. This
could provide remote monitoring or control of the boiler system.
Further, the processor (229) may provide additional information
instead of just indicating that a flood lockout or excessive feed
condition exists. For instance, the processor (229) may indicate
what fill event triggered the flood lockout or excess feed
condition and may also provide indications of current readings of
the processor, including the usage in the period and all the
recognized sub-periods, current or prior readings of the LWCO, the
time since the flood lockout occurred, and/or other information
that could be obtained by the processor (229). This additional
information can be reviewed by service personnel to detect the
potential problem or to quickly reset the system if there is no
actual problem.
[0056] The flood lockout condition will generally be able to be
overridden by maintenance personnel once they have determined that
the condition is acceptable or have fixed the underlying issue.
This reset will generally utilize the flood lockout reset (203) on
the water feed controller (101). Further, this override may occur
remotely, for instance, if maintenance personnel cannot immediately
come down to inspect the boiler, but it is important that the
boiler continue to run, the maintenance personnel may override the
flood lockout condition remotely via any of the previously noted
communication protocols.
[0057] In the embodiments of FIGS. 2 and 3, one additional function
is also included which is a manual fill button (213). The manual
fill button (213) allows a user to manually instruct the water feed
controller (201) to add additional water even if the LWCO is not
indicating a low water condition and if no other fill condition has
been implemented. The manual feed button (213) is essentially a
second way to fill the boiler in addition to opening manual by-pass
valve (105). However, using manual feed button (213) instead of
by-pass valve (105) provides the benefit of allowing maintenance
personnel to add extra water for whatever reason they think is
appropriate, while still making sure that such an addition is
logged as fill during the period for the processor's (229) excess
fill calculations. In this way, if the system is operating in LWCO
mode, maintenance personnel can raise the fill level above the
minimum, and still be notified if their action results in an
indication of excess water usage. In this way, a leak is more
likely to be detected regardless of the mode in which the system is
operating.
[0058] While the invention has been disclosed in connection with
certain preferred embodiments, this should not be taken as a
limitation to all of the provided details. Modifications and
variations of the described embodiments may be made without
departing from the spirit and scope of the invention, and other
embodiments should be understood to be encompassed in the present
disclosure as would be understood by those of ordinary skill in the
art.
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